The present invention relates to a thin film transistor (TFT) including an active layer made of an oxide conductor or silicon (Si), and a display including the thin film transistor.
Thin film transistors have been widely applied as fundamental technology for liquid crystal displays or organic EL (Electro Luminescence) displays. As a typical semiconductor film which is an active layer for the displays, a silicon (Si) film in a noncrystalline state (a so-called amorphous silicon film) or a polysilicon film crystallized by an excimer laser or solid-phase growth is used. Moreover, in recent years, it has been proposed that as a semiconductor film, a metal oxide capable of being formed by a low-cost apparatus such as a sputtering method is used.
In most of thin film transistors using a silicon film for an active layer, a light-shielding film is arranged to prevent light from entering the silicon film. Moreover, it has been known that in a metal oxide semiconductor, a change in electrical conductance occurs due to photoinduction (for example, refer to Japanese Unexamined Patent Application Publication No. 2007-115902 (FIG. 8)), so it has been proposed to arrange a light-shielding film.